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CVE-2026-20039 - Vulnerability Analysis

HighCVSS: 8.6

Last Updated: March 5, 2026

Cisco Secure Firewall ASA & FTD - Denial of Service

Published: March 4, 2026Updated: March 5, 2026Remote Exploitable

Overview

Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software contain a denial of service vulnerability caused by ineffective memory management in the VPN web server, letting unauthenticated remote attackers cause device reloads by sending crafted HTTP requests, exploit requires no special privileges.

Severity & Score

Severity: High

CVSS Score: 8.6

EPSS Score: 11.7%(Probability of exploitation in next 30 days)

Impact

Unauthenticated remote attackers can cause device reloads, resulting in denial of service.

Mitigation

Update to the latest available version of Cisco Secure Firewall ASA and FTD Software.

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-vpn-dos-SpOFF2Re

Social Media Activity(2 posts)

TheHackerWire

@thehackerwire

Mar 4, 2026

🟠 CVE-2026-20039 - High (8.6) A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) co... 🔗 https://www.thehackerwire.com/vulnerability/CVE-2026-20039/ #CVE #vulnerability #infosec #cybersecurity #security #Tenda #patchstack

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TheHackerWire

@thehackerwire

Mar 4, 2026

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Related Resources

Details

CVE ID: CVE-2026-20039
Severity: High
CVSS Score: 8.6
Type: denial_of_service
Status: unconfirmed
EPSS: 11.7%
Social Posts: 2

CWE

CWE-244

CVSS Metrics

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

EPSS Score

11.7%Probability of exploitation in the next 30 days